Discovered by Y. Väisälä MPC designation 2204 Lyyli Minor planet category Mars-crosser Absolute magnitude 12.7 Discoverer Yrjö Väisälä Asteroid group Mars-crosser asteroid | Discovery date 3 March 1943 Alternative names 1943 EQ · 1968 DN Discovered 3 March 1943 Orbits Sun Discovery site Iso-Heikkilä Observatory | |
Named after Lyyli Heinänen (Esperantist) Similar 132 Aethra, 2577 Litva, 1865 Cerberus, 323 Brucia, 2201 Oljato | ||
2204 Lyyli, provisional designation 1943 EQ, is a dark asteroid and very eccentric Mars-crosser from the middle region of the asteroid belt, approximately 25 kilometers in diameter. It was discovered on 3 March 1943 by Finnish astronomer Yrjö Väisälä at Turku Observatory in Southwest Finland.
The X-type asteroid orbits the Sun at a distance of 1.5–3.6 AU once every 4 years and 2 months (1,522 days). Its orbit has an eccentricity of 0.41 and an inclination of 21° with respect to the ecliptic. It has a rotation period of 11 hours and a very low albedo between 0.02 and 0.05, according to the surveys carried out by IRAS, Akari, and WISE/NEOWISE.
Other large Mars crossing minor planets include 132 Aethra and 323 Brucia, with diameters of 43 and 36 kilometers, respectively.
The asteroid was named in honour of Lyyli Heinänen (1903–1988), née Hartonen, a Finnish female Esperantist, professor of mathematics, amateur astronomer and former assistant of the discoverer. Naming citation was published on 26 May 1983 (M.P.C. 7944).